#include <iostream>
#include <string>
#include "ex2_42.h"

using std::cin;
using std::cout;
using std::endl;
using std::cerr;

int main()
{
	Sales_data data1, data2;

	// code to read into data1 and data2
	double price = 0;  // price per book, used to calculate total revenue

					   // read the first transactions: ISBN, number of books sold, price per book 
	cin >> data1.bookNo >> data1.units_sold >> price;
	// calculate total revenue from price and units_sold
	data1.revenue = data1.units_sold * price;

	// read the second transaction
	cin >> data2.bookNo >> data2.units_sold >> price;
	data2.revenue = data2.units_sold * price;

	// code to check whether data1 and data2 have the same ISBN
	//        and if so print the sum of data1 and data2
	if (data1.bookNo == data2.bookNo)
	{
		unsigned totalCnt = data1.units_sold + data2.units_sold;
		double totalRevenue = data1.revenue + data2.revenue;

		// print: ISBN, total sold, total revenue, average price per book
		cout << data1.bookNo << " " << totalCnt
			<< " " << totalRevenue << " ";
		if (totalCnt != 0)
			cout << totalRevenue / totalCnt << endl;
		else
			cout << "(no sales)" << endl;

		return 0;  // indicate success
	}
	else
	{  // transactions weren't for the same ISBN
		cerr << "Data must refer to the same ISBN" << endl;
		return -1; // indicate failure
	}
}
